UNCcoarse60° flank

3/4-10 UNC Thread Dimensions

3/4-10 UNC is a coarse pitch UNC thread. There are 10 threads per inch, giving a pitch of 2.54 mm. The recommended tap drill leaves roughly 75% thread engagement.

Nominal Ø19.05 mm
Pitch2.54 mm
Threads per inch10
Pitch Ø-22.85 mm
Tap drill-45.47 mm

Thread profile

millimetres unless stated
Thread profile — 3/4-10 UNCd 19.05d2 -22.85d3 -60.1mm60°P 2.54h3 39.58tap ⌀-45.47
3/4-10 UNC — basic profile60° flank angle · Not to scale
Designation
3/4-10 UNC
Thread system
UNC
Series
coarse
Flank angle
60°
Major diameter
19.05 mm / 0.75"
Pitch
2.54 mm
Threads per inch
10
Pitch diameter
-22.85 mm
Minor diameter (external)
-60.1 mm
Minor diameter (internal)
-50.79 mm
Thread depth
39.58 mm
Recommended tap drill
Ø -45.47 mm / -1.79"

How these values are derived

Basic ISO thread geometry uses the fundamental triangle height H = 0.866025 × P. External minor diameter d₃ = d − 1.226869 × P, internal minor diameter D₁ = d − 1.082532 × P. Tap drill is given as nominal diameter minus pitch, which approximates a 75% thread engagement — adjust for tough materials or deep holes.